Remember when you were a kid and you dropped your cookie on the floor, but immediately scooped it back up because of the almighty “five-second rule”? Whether you adhere to that bacterial code of conduct or dismiss it as an old wives’ tale, the five-second rule — believe it or not — has been the subject of scientific debate for some time. Scientists generally conclude it all has to do with the cleanliness of your floor and wetness of the dropped food.
A recent study from Aston University in Birmingham, England, goes into even more depth: Pasta, candy, and toast with the butter side down can be snatched up and eaten with (usually) no problem within five seconds. However, certain drier, crunchier foods can be left on the floor for up to 30 minutes like potato chips, cookies, and unbuttered toast. The reason for this is that softer, wetter foods pick up bacteria a lot more readily than drier foods.
Not only that, but the floor texture matters a lot. According to the research, which tested out bacteria accumulation on different foods and floor types, dropping food on carpet or rugs was a lot safer than on tile or laminated floors, where bacteria latch on quicker.
But even if you eat a ripe raspberry or cooked noodle off of your grimy linoleum tile, chances are you won’t get sick. Scientists concluded most of the substance that stuck to the surface of fallen foods was made of dead skin or hair cells.
“Obviously, food covered in visible dirt shouldn’t be eaten, but as long as it’s not obviously contaminated, the science shows that food is unlikely to have picked up harmful bacteria from a few seconds spent on an indoor floor,” lead researcher Anthony Hilton told The Daily Mail.